Apparatus for perforating well casings



Oct. 28, 1930.

C. E. WOOD APPARATUS PoR PERFORMING wBLL cAsINGs Filed Dec4 l0` 1929 2 Sheets-Sheet l oct. 2s, 1930. Q E. WOD 1,779,652 I APPARATUS FOR PERFORATING WELL CASINGS Filed Dec. l0, 1929 2 SheetS-She et 2 l fw 'Jh/6 fforneys. l

Patented Oct.. 930- Enwm wool), or Los aNeELEs, m0333145 mmrUs-:l'on mantenerme WELL casi-NGS" .Application filed December io, 1

This invention relates to an apparatus for perforating well casings' and the principal ob- )ect is to provide such an apparatus having a single kmfe constructed and arranged so 1t can be driven out through one or more wellv casings to form large slots through which oil i or water can enter `the inner casing, with means for centraliz'in the ap aratus in the inner casing while the 'fe is being actuated l0 to thereby avoid unnecessary frictlonal contact between the apparatus and casing while f the perforating is being accomplished.

Another object of the invention is to provide a simple positive means for starting and forcing the cutting point of the knife into and through lthe wall of the inner casing, which movements are accomplished by means of a thrust cam acting on the free end of the knife to actuate it as stated. Ihat is, the cam is actuated to cause the cutting point of the knife to engage with the inner wall of the inner casing and force itto break through the wall.

ature of invention is shown in the con-- Y struction and arrangement of the perforating knife in the apparatus whereby only its cut-k tingv point will first engage the inner .wall of the casing when actuated, -as the end portion of the knife carrying the cutting point is olfset edgewise to the body of the knife, so that only the cutting pcint canengage the wall in the initial movement of the knife to perforate a casing.

85 Another feature of invention is shown in of the thrust cam whereby it is operated to engage and thrust the cutting point of the knife through the casing'and simultaneously engage the opposite side of the casing wall and hold the apparatus central in the casing while the knife is being driven through the wall. f

' Another and important new `feature of the 5^ invention consists in the relative arrangement of the parts s o as to centralize the thrust of the knife and cam within the inner casing. Thus the lmife and cam are centrally pivoted there-` in and coact so that the knife turns 4one way `lng-drawings, the subjoined detailed descripthe construction, arrangement and operation and the cam the opposite way, and both simulrm-3. das@ l l taneously engage op ositewalls of the inner tube, substantially as vereinafter explained.A

' Other objects, advantagesand features of invention may appearfrom theaccompanytion and the appended claims.` 5s

The accompanying drawings illustrate the invention.

Figure 1 is a perspective v iew of an apparatus for perforating well casings that is cono structed "in accordance with this. invention, vshowing ita-arranged in a well casing and connected tothe usual spring sto' appliance, the casing, drill rod and stein ofp the stop apparatus beingshown in section. i v

Figfgis acentral -vertical section on line 2 2, Fig. 1, showing the'knife and thrust cam in anormal idle position and showing the stop appliance released from the apparatus and the, wedgeblock in position to actuate the. cam; also showing an inner and outer casing.

-F ig. 3 is a view-analogous to Fig. 2, showing the apparatus moved down .on the wedge block so that it has actuated the thrust cam to engagle the casing wall at one point and force out t e knife in an 'opposite direction so its cutting point is engaged with and thrust v throughv the wall-of the inner casing.

. Fig. 4 is a view analogous to Fig. 3, showing 89 i the arrangement of the ratus has formed slots in both the inner and parts after the appaouter casings, also showing by dotted lines a cementitious wall of the well through which the free end of the knife is also extended. v

Fig.'5 is a cross section on line 5 5, Fig. 4.

Fig. 6 is an enlarged side view of the knife showing its cutting oint offset edgewise from the body of the kni e.

Fig. 7 is an edge view of the knife.

The apparatus for perforating well casings includes a tubular housing 10 haVing a threaded stem 11 at its upper end by which it can'be detachably connected to'a hollow drill rod 12 that is actuated in the usual way well 95 known in the art.

Also the housing 10 has a threaded stem 13. at its lower end that is detachably connected to one end of a sleeve14 that has itsother end secured to a stem 15 of a spring stop 16. The 100 stem 13 preferably has a left hand thread so that the spring stop can be disconnected from the apparatus whenever desired by rotating the drill rod to the right and can be `recon-' nected by a reverse rotation of the rod.

The construction and operation of thespring stop 16 are old and well understood in the art and for that reason is shown semidiagrammaticall itbeing understood that when detached rom 4the apparatus the bow j s`he cam 22 ,isl pivotally mounted on a pinv 23 in the housing 10 and arranged so it can be engaged at one side of its pivot by a wedge 24 on the movable block 21, and thereby actuated so that the toothed extension 25 of the cam will be moved upwardly from the position in Fig. 2`to theA position in Fig. 3 to enga e the inside wall of the inner casing 26.

imultaneously with this initial movement of the cam, itscurved thrust-extension 27 will en age the'rear side of the lower end of the knife 28, as shown in Fig. 2, and move its cuttin point 29 outward into engagement with t e inner wall of the inner casing 26 opposite, but slightly above the point engaged b the toothed entension 25 of cam 22, as s own in Fig. 3.

The knife 28 is pivotally mounted on a in 30 in the housing 10 and is of considera le length so that it can be driven to penetrate both the inner casing 26 and outer casing 31 and also break throu h thev cementitious It is noted that Athe housing 1() is cylindri-v cal and nearly as large as the inner casing 26 so as to be loosely moved downward therein,

and that the cam 22 is pivoted in housing 10 beneath the pivot of the knife 28 in the housing and both are pivoted centrally ofthe housing 10 and inner casing 26, as shown.

Since the cam and knife act against each other with a lateral thrust, as shown in ,Fi 3, there is a balanced action self-containe in the inner casin 26 withthe two members 22 and 28 presslng against substantially o posite walls of the casing. Hence this avoi s any tendency of the parts to throw all the of the-center of the inner casing or against the side wall of such casing'and at one point, so as to s ide track' the thrust or distort the inner casing.

After theknife has been forced through. the casing 26 and the housing 10 and apparatus forced further downward in the well, the knife 28 will be moved in an arc so that its `cutting point will .be forced outwardl through the outer casing 31 and also brea the cementitious wall 32 and the arc movement of the knife will be continued until its Y edge 33 is engaged bythe shoulder 34 of the housing 10, after which the knife will move fter the cam 22 has driven the knifev through the inner casing 28, it becomes idle and returns to a normal position when the apparatus is moved upward to release thc knlfe from the slots so it can return to a normal position.

'In operation the apparatus is actuated as described, the cam moving to force the cutting point of the knife through the inner c asin after which it becomes idle.

I c aim as my invention:

1. Apparatus for perforating well casings, includin a housing, a knife pivotally mounted thereln, a thrust cam ivot-ally mounted in said housing for engaging the well casing at one point and forcing said knife to penetrate the casing at a point, substantially opposite to the point engaged by said cam so that said housing is centralized in said casing while said lmife is being actuated.'

2. Apparatus for erforatln well casings, including a hollow ousing, a ifeppivotally mounted in said housing, a thrust cam pivoted in said housing below said knife, a wedge block for actuating said cam to cause it to engage the well casing at one point and as it is actuated to engage and move said knife to cause itto penetrate the casing at a pointsubstantially opposite to that engaged by said cam, and means for holding said wedge block stationary while said housing is forced downward in the well casing.

3. In apparatus for perforating well casings the combination of a housing, a wedgel block slidably mounted therein, a stop detachros ably conneetedto said housing for holding said wedge block in a stationary position, a cam pivotally mounted in said housing above and adjacent said wedge block, a lknife pivotally mounted in said housing` above said cam, a toothedextension on the cam arranged to engage the well casing when said cam is actuated by movement of said housing towardsaid wedge block, a convex thrust extension on said cam for engaging and forcing said knife through the well casing at a point subdown thrust on the housing toward one side `stalitially oppositeto. that engaged Aby said toothed extension, so that said housing is centralized while said` knife is being driven through the casing, and means for actuating said housing toward said wedge block.

A so

In witness whereof, I have hereunto af- 

